Cooperative control method and device for hard and thick roof of coal face

Abstract

The invention discloses a cooperative control method and device for a hard and thick top plate of a coal face. The method comprises the steps that whether the coal face meets cooperative control conditions or not is determined; if the coal face meets the cooperative control condition, determining process parameters of the to-be-fractured area corresponding to the hard and thick roof; hydraulic support supporting parameters of the coal face are determined, and a target hydraulic support is determined based on the hydraulic support supporting parameters; and performing cooperative control on the hard and thick top plate of the coal face based on the process parameters of the to-be-fractured area and the target hydraulic support. According to the method, cooperative control over the surrounding rock of the super-thick coal seam coal face is carried out through super-high resistance support powerful supporting of the target hydraulic support and the underground area fracturing technology based on the technological parameters of the area to be fractured, the mine pressure appearance strength of the coal face is effectively reduced, and the stoping safety of the coal face is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of coal seam mining, and particularly to a collaborative control method and device for a hard and thick roof in a coal mining face. Background Art

[0002] At present, the coal resources reserves in thick and extra-thick coal seams are abundant. The main coal seams mined in ten-million-ton mines are mostly thick and extra-thick coal seams. Among them, the reserves of coal seams more than 10 m thick may exceed 50 billion tons, which are important strategic resources for the continuous and stable supply of national energy.

[0003] Among them, for the coal seam roof mainly composed of extra-thick, hard and stable sandy rock strata, there are multiple hard and thick roofs above the coal seam. Along with the high-intensity mining of the extra-thick coal seam working face, the strong mine pressure phenomenon caused by the breaking of the thick and hard roof is extremely strong. Moreover, the maximum working resistance of the hydraulic support in this fully-mechanized caving face is 21,000 kN, and the maximum working resistance of the hydraulic support in the large mining height fully-mechanized coal mining face is 29,000 kN. However, strong mine pressure problems such as significant shrinkage of the support, even roof cutting and support pressing, and roof caving still occur, posing a great threat to the safe production of the working face. Due to the high mining intensity, large mined-out space and the action of multiple thick and hard roofs in the extra-thick coal seam working face, the overlying rock movement is intense, and the intensity of mine pressure manifestation and the difficulty of surrounding rock control show a geometric increase compared with that of a general fully-mechanized coal mining face.

[0004] Moreover, at present, the all-caving method is mainly used to manage the roof in longwall mining working faces. The hydraulic support is the main equipment for roof support and surrounding rock control in the fully-mechanized coal mining face. After the working face is mined, the roof in the goaf behind the support immediately collapses, and the load of the overlying rock strata is jointly borne by the coal wall, the hydraulic support and the caved gangue in the goaf. Among them, the traditional theory of mine pressure and strata control holds that according to the degree of damage, the roof in the goaf behind the support forms three roof zones from bottom to top, namely the caving zone, the fissure zone and the bending subsidence zone. The height of the caving zone is generally 2 to 4 times the mining height. The roof strata directly above the coal seam that can collapse as the working face is mined are called the immediate roof. The immediate roof can be composed of multiple continuous, weak and thin rock strata, generally with the characteristics of low occurrence horizon, weak strength and thin thickness. The thick and hard rock strata directly above the immediate roof (sometimes directly above the coal seam in the case of the absence of the immediate roof) that directly affect the mine pressure in the stope are called the main roof. The periodic breaking of the main roof causes the periodic weighting of the working face.

[0005] Furthermore, in a fully mechanized coal mining face with a general mining height, when the immediate roof can be filled into the goaf after caving and swelling, the thickness of the immediate roof is basically equal to the height of the caving zone. The main roof can timely contact the caved gangue under the support of the caved gangue in the caving zone to form a stable structure, and it is not easy to cause obvious strong mine pressure. Based on this, in the above situation, through the reasonable selection of hydraulic supports, the effective control of the surrounding rock of the working face can be achieved. However, in the coal mining face of extra-thick coal seams, the activity space of the roof increases significantly, and the height of the caving zone moves up. The hard rock of the main roof in the traditional concept is located within the caving zone and cannot form a stable articulated structure, but acts on the mine pressure of the working face in the form of a cantilever beam. Due to the insufficient filling of the goaf, it is easy to cause dynamic load impact on the supports and obvious strong mine pressure during periodic fracture. Based on this, it is difficult to effectively control the roof simply by using hydraulic support, and thus it has been unable to effectively solve the problem of strong mine pressure caused by the thick and hard roof in the coal mining face of extra-thick coal seams. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0007] For this purpose, the present invention provides a collaborative control method for the hard and thick roof of a coal mining face, which can perform collaborative control on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support, so as to carry out collaborative control on the surrounding rock of the coal mining face of extra-thick coal seams through the strong support of the ultra-high resistance support of the target hydraulic support and the area fracturing technology based on the process parameters of the area to be fractured underground, effectively reducing the intensity of the mine pressure appearance on the working face and ensuring the mining safety of the coal mining face.

[0008] Another object of the present invention is to provide a collaborative control device for the hard and thick roof of a coal mining face.

[0009] To achieve the above object, on the one hand, the present invention provides a collaborative control method for the hard and thick roof of a coal mining face, and the method includes:

[0010] Determine whether the coal mining face meets the collaborative control conditions;

[0011] If the coal mining face meets the collaborative control conditions, determine the process parameters of the area to be fractured corresponding to the hard and thick roof;

[0012] Determine the support parameters of the hydraulic support of the coal mining face, and determine the target hydraulic support based on the support parameters of the hydraulic support;

[0013] Perform collaborative control on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support.

[0014] The collaborative control method for the hard and thick roof of the coal mining face in the embodiments of the present invention may further have the following additional technical features:

[0015] In one embodiment of the present invention, determining whether the coal mining face meets the collaborative control conditions includes:

[0016] Determining a first height of the caving zone and a second height of the fissure zone corresponding to the coal mining face;

[0017] Based on the first height and the second height, determining whether there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining face;

[0018] If there is no hard and thick rock stratum or key stratum within the caving zone of the coal mining face, determining the target working resistance of the hydraulic support corresponding to the first structure;

[0019] If there is a hard and thick rock stratum or key stratum within the caving zone of the coal mining face, determining the target working resistance of the hydraulic support corresponding to the second structure;

[0020] Based on the target working resistance, determining whether the coal mining face meets the collaborative control conditions.

[0021] In one embodiment of the present invention, determining the target working resistance of the hydraulic support corresponding to the first structure includes: determining the target working resistance of the hydraulic support corresponding to the first structure through a first formula, where the first formula is:

[0022]

[0023] Wherein, the B is the center distance of the hydraulic support; the l k is the roof control distance; the Σh1 is the thickness of the immediate roof; the γ z is the unit weight of the immediate roof; the L is the periodic weighting interval of the main roof; the is the friction angle between rock blocks; the α is the fracture angle of the rock block; the h1 is the thickness of the main roof; the S1 is the subsidence amount of the broken rock block of the main roof; the Q is the total weight of the exposed rock blocks in the lower strata of the fissure zone above the working face roof.

[0024] In one embodiment of the present invention, determining the target working resistance of the hydraulic support corresponding to the second structure includes: determining the target working resistance of the hydraulic support corresponding to the second structure through a second formula, where the second formula is:

[0025]

[0026] Wherein, the h 垮 is the distance from the roof interface rock stratum of the caving zone to the coal seam; the h2 is the thickness of the lower strata of the fissure zone; the L1 is the cantilever length of the cantilever beam; the L2 is the periodic caving interval of the hard rock stratum; the S2 is the subsidence amount of the lower strata of the fissure zone.

[0027] In one embodiment of the present invention, the process of determining the process parameters of the hard and thick roof corresponding to the area to be fractured includes:

[0028] Determine the fracture pressure of the hydraulically fractured rock formation according to the in-situ stress field data and the rock tensile strength of the area to be fractured, so as to determine the target hydraulic fracturing pumping station;

[0029] Determine the hydraulic fracture propagation radius of the area to be fractured;

[0030] Determine the borehole layout plan according to the distribution parameters of the hard and thick roof;

[0031] Determine the staged fracturing spacing according to the hydraulic fracture propagation radius.

[0032] In one embodiment of the present invention, the collaborative control of the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support includes:

[0033] Actively support the near-field roof of the mined-out space of the coal mining face through the target hydraulic support;

[0034] According to the borehole layout plan, the fracture pressure and the staged fracturing spacing, use a straddle packer to perform staged backward fracturing in the borehole to perform staged fracturing on the boreholes in the area to be fractured until the end fracturing condition is met, then stop the pump to end the fracturing.

[0035] In one embodiment of the present invention, the method further includes:

[0036] Obtain the monitoring and analysis results during the collaborative control process;

[0037] Evaluate the collaborative control according to the monitoring and analysis results to obtain an evaluation result;

[0038] Based on the evaluation result, dynamically adjust the process parameters of the fracturing area.

[0039] On the other hand, the present invention proposes a collaborative control device for the hard and thick roof of a coal mining face, and the device includes:

[0040] A first determination module, configured to determine whether the coal mining face meets the collaborative control conditions;

[0041] A second determination module, configured to determine the process parameters of the hard and thick roof corresponding to the area to be fractured if the coal mining face meets the collaborative control conditions;

[0042] A third determination module, configured to determine the hydraulic support parameters of the coal mining face and determine the target hydraulic support based on the hydraulic support parameters;

[0043] A collaborative control module for collaboratively controlling the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support.

[0044] The collaborative control method and device for the hard and thick roof of the coal mining face according to the embodiments of the present invention can collaboratively control the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support. Thus, the collaborative control of the surrounding rock of the extra-thick coal seam mining face can be carried out through the strong support of the ultra-high resistance support of the target hydraulic support and the area fracturing technology based on the process parameters of the area to be fractured underground, effectively reducing the intensity of the mine pressure appearance on the working face and ensuring the mining safety of the coal mining face.

[0045] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, wherein:

[0047] Figure 1 is a flowchart of a collaborative control method for the hard and thick roof of a coal mining face according to an embodiment of the present invention;

[0048] Figure 2 is a schematic diagram of determining the key strata of the roof rock stratum according to an embodiment of the present invention;

[0049] Figure 3a is a schematic diagram of no hard and thick rock stratum or key stratum within the caving zone of a coal mining face according to an embodiment of the present invention;

[0050] Figure 3b is a schematic diagram of having a hard and thick rock stratum or key stratum within the caving zone of a coal mining face according to an embodiment of the present invention;

[0051] Figure 4a is a schematic diagram of no hard and thick rock stratum or key stratum within the caving zone of a coal mining face according to an embodiment of the present invention;

[0052] Figure 4b is a schematic diagram of having a hard and thick rock stratum or key stratum within the caving zone of a coal mining face according to an embodiment of the present invention;

[0053] Figure 5 is a schematic diagram of a three-dimensional lidar scanning the void in the goaf behind the support according to an embodiment of the present invention;

[0054] Figure 6 is a schematic diagram of collaborative control according to an embodiment of the present invention;

[0055] Figure 7 is the curve graph of the final resistance of the support cycle according to an embodiment of the present invention;

[0056] Figure 8 is the frequency distribution graph of the final resistance of the support cycle according to an embodiment of the present invention;

[0057] Figure 9 is the statistical graph of the average initial support force of the working face support according to an embodiment of the present invention;

[0058] Figure 10a is the plan view of the microseismic event distribution according to an embodiment of the present invention;

[0059] Figure 10b is the sectional view of the microseismic event distribution according to an embodiment of the present invention;

[0060] Figure 11 is the structural diagram of the collaborative control device for the hard and thick roof of the coal mining face according to an embodiment of the present invention. Detailed implementation manners

[0061] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0062] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] The collaborative control method and device for the hard and thick roof of the coal mining face according to the embodiments of the present invention will be described below with reference to the drawings.

[0064] Figure 1 is the flowchart of the collaborative control method for the hard and thick roof of the coal mining face in the embodiment of the present invention.

[0065] As Figure 1 shown, the method may include the following steps:

[0066] Step 101, determine whether the coal mining face meets the collaborative control conditions.

[0067] In an embodiment of the present invention, the method for determining whether the coal mining face meets the collaborative control conditions may include the following steps:

[0068] Step 1011: Determine the first height of the caving zone and the second height of the fissure zone corresponding to the coal mining face.

[0069] Step 1012: Based on the first height and the second height, determine whether there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining face.

[0070] Step 1013: If there is no hard and thick rock stratum or key stratum within the caving zone of the coal mining face, determine the target working resistance of the hydraulic support corresponding to the first structure.

[0071] Step 1014: If there is a hard and thick rock stratum or key stratum within the caving zone of the coal mining face, determine the target working resistance of the hydraulic support corresponding to the second structure.

[0072] Step 1015: Based on the target working resistance, determine whether the coal mining face meets the collaborative control conditions.

[0073] In an embodiment of the present invention, the first height of the caving zone and the second height of the fissure zone corresponding to the coal mining face can be determined by using the two-zone actual measurement method, the empirical formula method, or the leakage volume observation method according to the coal seam occurrence and mining conditions of the coal mining face. Among them, the detailed introduction of the two-zone actual measurement method, the empirical formula method, and the leakage volume observation method can refer to the prior art, and the embodiments of the present disclosure will not elaborate herein.

[0074] Among them, in an embodiment of the present invention, after obtaining the first height and the second height, it is possible to determine whether there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining face based on the first height and the second height. Specifically, in an embodiment of the present invention, based on the first height and the second height, the key stratum position above the working face can be analyzed according to the roof structure and the mechanical properties of the rock stratum to determine whether there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining face. Figure 2 This is a schematic diagram for determining the key stratum of the roof rock stratum provided by the embodiments of the present disclosure. As Figure 2 shown, if there is medium-grained sandstone with a thickness of 17.8 m and an accumulated thickness of 82.82 m on the roof rock stratum, it is determined that there is a key stratum within the caving zone of the coal mining face.

[0075] In addition, in an embodiment of the present invention, if there is no hard and thick rock stratum or key stratum within the caving zone of the coal mining face (as Figure 3a shown, 1 - extra-thick coal seam; 2 - hard and thick roof; 3 - top boundary of the caving zone; 4 - top boundary of the fissure zone), the target working resistance of the hydraulic support corresponding to the first structure is determined. Among them, in an embodiment of the present invention, the above-mentioned first structure can be a hinged rock beam structure (as Figure 4a shown).

[0076] Among them, in an embodiment of the present invention, the method for determining the target working resistance of the hydraulic support corresponding to the first structure may include: determining the target working resistance of the hydraulic support corresponding to the first structure through a first formula, where the first formula is:

[0077]

[0078] Among them, B is the center distance of the hydraulic support; l k is the roof control distance; Σh1 is the thickness of the immediate roof; γ z is the bulk density of the immediate roof; L is the periodic weighting interval of the main roof; is the friction angle between rock blocks; α is the fracture angle of rock blocks; h1 is the thickness of the main roof; S1 is the subsidence of the broken rock block of the main roof; Q is the total weight of the exposed rock blocks in the lower strata of the fracture zone above the working face roof.

[0079] Further, in an embodiment of the present invention, if there are hard and thick strata or key strata (as shown in Figure 3b ) within the caving zone of the coal mining face, then determine the target working resistance of the hydraulic support corresponding to the second structure. Among them, in an embodiment of the present invention, the above-mentioned second structure may be a cantilever beam and a hinged rock beam structure (as shown in Figure 4b ).

[0080] Among them, in an embodiment of the present invention, the method for determining the target working resistance of the hydraulic support corresponding to the second structure may include: determining the target working resistance of the hydraulic support corresponding to the second structure through a second formula, where the second formula is:

[0081]

[0082] Among them, h 垮 is the distance from the roof interface strata of the caving zone to the coal seam; h2 is the thickness of the lower strata of the fracture zone; L1 is the cantilever length of the cantilever beam; L2 is the periodic caving interval of the hard strata; S2 is the subsidence of the lower strata of the fracture zone.

[0083] In addition, in an embodiment of the present invention, according to the structural characteristics of the specific roof, the working resistance required for the hydraulic support to support the roof can be calculated using the first formula or the second formula to determine the target working resistance of the hydraulic support.

[0084] Further, in an embodiment of the present invention, after obtaining the target working resistance through the above steps, it is possible to determine whether the coal mining face meets the cooperative control conditions based on the target working resistance. Specifically, in an embodiment of the present invention, the method for determining whether the coal mining face meets the cooperative control conditions based on the target working resistance may include: If there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining face, it is determined whether there is a hydraulic support that meets the target working resistance. If there is no hydraulic support that meets the target working resistance, it is determined that the coal mining face meets the cooperative control conditions.

[0085] For example, in an embodiment of the present invention, assuming that the above target working resistance is 50000 kN and the maximum working resistance of the current extra-high mining height hydraulic support is 29000 kN, that is, there is no hydraulic support that meets the target working resistance and it is impossible to meet the roof support requirements, then it is determined that the coal mining face meets the cooperative control conditions.

[0086] In another embodiment of the present invention, the method for determining whether the coal mining face meets the cooperative control conditions based on the target working resistance may further include: If there are obvious strong mine pressure manifestations caused by the action of a hard roof at the site of the extra-thick coal seam mining face and there are obvious phenomena such as the shrinkage of the support columns of the hydraulic support and the risk of support pressing, then it is determined that the coal mining face meets the cooperative control conditions.

[0087] In yet another embodiment of the present invention, the method for determining whether the coal mining face meets the cooperative control conditions based on the target working resistance may further include: Observing the roof gangue caving and filling conditions in the goaf behind the support by means of manual observation or three-dimensional lidar. If there is a phenomenon of non-collapse in the goaf behind the support, for example, obvious cavities (as Figure 5 shown), then it is determined that the coal mining face meets the cooperative control conditions.

[0088] Step 102, if the coal mining face meets the cooperative control conditions, determine the process parameters of the area to be fractured corresponding to the hard and thick roof.

[0089] In an embodiment of the present invention, after determining that the coal mining face meets the cooperative control conditions through the above steps, the process parameters of the area to be fractured corresponding to the hard and thick roof can be determined.

[0090] Specifically, in an embodiment of the present invention, the method for determining the process parameters of the area to be fractured corresponding to the hard and thick roof may include the following steps:

[0091] Step 1021, determine the fracture pressure of the hydraulically fractured rock stratum according to the in-situ stress field data and the rock tensile strength of the area to be fractured to determine the target hydraulic fracturing pumping station;

[0092] Step 1022, determine the hydraulic fracture propagation radius of the area to be fractured;

[0093] Step 1023: Determine the borehole layout plan according to the distribution parameters of the hard and thick roof.

[0094] Step 1024: Determine the staged fracturing spacing according to the hydraulic fracture propagation radius.

[0095] Among them, in an embodiment of the present invention, the breakdown pressure of the hydraulically fractured rock formation can be determined according to the in-situ stress field data and the rock tensile strength of the area to be fractured, and the target hydraulic fracturing pumping station capable of withstanding the corresponding high pressure can be determined based on the breakdown pressure. Among them, the third formula is:

[0096] P b = 3σ h -σ H +σ t

[0097] Among them, P b is the breakdown pressure of the rock formation, σ h is the minimum horizontal principal stress, σ H is the maximum horizontal principal stress, σ t is the rock tensile strength.

[0098] In addition, in an embodiment of the present invention, the rock mechanical parameters and fracturing fluid parameters can be obtained, and the numerical simulation software FracproPT can be used to calculate the hydraulic fracture propagation size under different fluid volumes to determine the hydraulic fracture propagation radius of the area to be fractured.

[0099] Further, in an embodiment of the present invention, the number of borehole layers can be determined according to the number of hard roofs to determine the borehole layout plan, and a hydraulic drill can be used to drill boreholes parallel to the rock formation into the hard rock formation.

[0100] Among them, in an embodiment of the present invention, the number of boreholes in the working face advancing direction and the length direction can be determined according to the geometric dimensions of the working face. Specifically, in an embodiment of the present invention, in the working face advancing direction, m boreholes are arranged in a straight line to cover the entire working face advancing length. For example, if the working face advancing length is L t , the borehole length is L h , then m boreholes need to be arranged in the working face to cover the advancing length, m = L t ÷L h .

[0101] In an embodiment of the present invention, in the working face length direction, n parallel boreholes are arranged, and the spacing d of the parallel boreholes is determined according to the fracture propagation radius r, D h ≥2r. For example, if the working face length is L c, then n boreholes need to be arranged on the working face to cover the length of the working face, and n = L c ÷D h . Based on this, the total number of boreholes arranged on the entire working face is m×n.

[0102] Also, in an embodiment of the present invention, a straddle packer can be used to perform staged backward fracturing in the borehole to perform staged fracturing on the borehole. Among them, the staged fracturing spacing D f can be determined according to the fracture propagation radius r, and D f ≥2r.

[0103] Step 103, determine the support parameters of the hydraulic supports in the coal mining face, and determine the target hydraulic supports based on the support parameters of the hydraulic supports.

[0104] In an embodiment of the present invention, from the perspective of facilitating the control of the roof and rib spalling of the working face, determine the support parameters of the hydraulic supports in the coal mining face, and select the type of hydraulic supports based on the support parameters of the hydraulic supports to determine the target hydraulic supports. Among them, in an embodiment of the present invention, the support parameters of the hydraulic supports may include working resistance, support type, and rib protection form.

[0105] Among them, in an embodiment of the present invention, the above-mentioned target working resistance can be used as the working resistance to be achieved. Also, in an embodiment of the present invention, the support type and rib protection form of the hydraulic supports can be determined according to manual experience.

[0106] Step 104, perform coordinated control on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic supports.

[0107] Among them, in an embodiment of the present invention, after determining the process parameters of the area to be fractured and the target hydraulic supports through the above steps, coordinated control can be performed on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic supports (as Figure 6 shown).

[0108] Specifically, in an embodiment of the present invention, the method for performing coordinated control on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic supports may include the following steps:

[0109] Step 1041, actively support the near-field roof of the mined-out space in the coal mining face through the target hydraulic supports;

[0110] Step 1042, according to the borehole layout plan, fracture pressure, and staged fracturing spacing, use a straddle packer to perform staged backward fracturing in the borehole to perform staged fracturing on the boreholes in the area to be fractured until the end-fracturing condition is met, then stop the pump to end the fracturing.

[0111] Among them, in one embodiment of the present invention, the above-mentioned end-fracturing conditions may include sufficient fracture propagation.

[0112] Specifically, in one embodiment of the present invention, a hydraulic fracturing pump pressure and flow monitoring system can be used to obtain a hydraulic fracturing pump pressure curve, and based on the hydraulic fracturing pump pressure curve, the volume of the injected liquid and the effective fracture formation time are determined. And within the effective fracture formation time, it is determined whether the fracture reaches the borehole based on the water output situation of adjacent boreholes. If the fracture reaches the borehole, it is determined that the fracture propagation is sufficient; if the fracture does not reach the borehole, it is determined that the fracture propagation is not sufficient.

[0113] Furthermore, in one embodiment of the present invention, after the hard and thick roof of the coal mining face is co-controlled based on the process parameters of the area to be fractured and the target hydraulic support, the above method may include the following steps:

[0114] Step 105, obtaining the monitoring and analysis results during the co-control process;

[0115] Step 106, evaluating the co-control according to the monitoring and analysis results to obtain an evaluation result;

[0116] Step 107, dynamically adjusting the process parameters of the fracturing area based on the evaluation result.

[0117] Among them, in one embodiment of the present invention, the method for obtaining the monitoring and analysis results during the co-control process may include the following steps:

[0118] Step 1: Use a mine pressure monitoring system to monitor the stress condition of the target hydraulic support in real time to obtain the matching degree between the support support capacity and the mine pressure intensity of the working face;

[0119] Among them, in one embodiment of the present invention, a mine pressure monitoring system can be used to monitor the end-of-cycle resistance of the support (the working resistance of the support at the end of a coal mining cycle, as Figure 7 shown) of the target hydraulic support during a period of multiple coal mining cycles in the normal coal mining process of the extraction working face in real time, and based on the end-of-cycle resistance of the support, obtain the matching degree between the support support capacity and the mine pressure intensity of the working face.

[0120] Specifically, assume that the rated working resistance of the support is P 额 , and the end-of-cycle resistance of the support is P t . If the proportion of the end-of-cycle resistance of the support distributed within the range of 60% to 95% of the rated working resistance of the support exceeds the first target value W1, it is considered that the matching degree between the support support capacity and the current mine pressure intensity of the working face is good and the support type selection is reasonable; if the data of the end-of-cycle resistance of the support greater than 95% of the rated working resistance (P t >0.95*P 额) exceeds the second target value W2, indicating that the support capacity of the support does not match the intensity of the mine pressure on the working face, the selected support is too small, or the intensity of the hard roof fracturing needs to be increased. Among them, the above first target value and second target value can be set as needed, and the second target value is less than the first target value. For example, the first target value is 80%, and the second target value is 20%.

[0121] Step 2: Use the microseismic monitoring system to monitor the large-energy microseismic events on the working face roof to obtain the large-energy microseismic event level;

[0122] Among them, when using the microseismic monitoring system to monitor the large-energy microseismic events on the working face roof, if the large-energy microseismic event levels in the monitoring results are mainly distributed below 10 4 J, and the proportion of large-energy microseismic events exceeding 10 4 J does not exceed the third target value W3, it is considered that the fracturing effect of the hard roof is good; otherwise, it is considered that the fracturing effect of the hard roof is poor. Among them, the third target value can be set as needed. For example, the third target value is 5%.

[0123] Step 3: Use a 3D lidar to observe the filling degree of the goaf behind the working face support to obtain the filling degree result;

[0124] Among them, in an embodiment of the present invention, when using a 3D lidar to observe the filling degree of the goaf behind the working face support, if the volume of the scanned cavity in the goaf behind the support is less than the fourth target value W4, it indicates that the roof has collapsed sufficiently and the fracturing effect of the hard roof is good, then the filling degree result is good; otherwise, the filling degree result is poor. Among them, the fourth target value can be set according to experience, such as 10m 3 .

[0125] In addition, in an embodiment of the present invention, the collaborative control can be evaluated based on the above-mentioned matching degree between the support capacity of the support and the intensity of the mine pressure on the working face, density and horizon changes, and filling degree result to obtain an evaluation result. Among them, in an embodiment of the present invention, the above evaluation result can include good and poor.

[0126] Further, in an embodiment of the present invention, when the above evaluation result is poor, the process parameters of the fracturing area can be dynamically adjusted according to the monitoring results and the analysis results of the main rock strata of the strong mine pressure.

[0127] It should be noted that in an embodiment of the present invention, for the collaborative control method of the hard and thick roof in the coal mining face, an ultra-high resistance target hydraulic support is used to actively support the near-field roof of the ultra-large extraction space. The ultra-high support resistance of the hydraulic support inhibits the subsidence and separation of the near-field roof, improves the overall stiffness of the support-surrounding rock system, maintains the stability of the near-field surrounding rock structure in the stope, and avoids roof cutting near the coal wall of the thick and hard roof. Through the ultra-high roof cutting force acting on the roof, the roof cutting line is forced to move backward, changing the fracture position and suspended roof state of the near-field roof, reducing the pressure of roof rotation on the coal wall, and alleviating coal wall spalling. The regional fracturing technology based on the process parameters of the area to be fractured underground is used to actively relieve and weaken the far-field multi-layer thick and hard roof, reduce the thickness, fracture block size and suspended roof distance of the hard roof layers, improve the swelling and filling degree of the roof gangue in the goaf, improve the stress environment in the stope, change the fracture structure of the overlying strata in the near and far fields of the ultra-large extraction space, and reduce the dynamic load impact of the fracture and instability of the multi-layer thick and hard roof on the support-surrounding rock system in the stope.

[0128] Moreover, in an embodiment of the present invention, the above-mentioned target hydraulic support and fracturing method act synergistically in terms of time and space. Among them, time synergy means that before the mining influence of the working face, the roof is first modified and weakened through regional pressure relief, creating a large number of mainly horizontal crack networks in the originally intact rock mass, prompting the hard and intact roof to be pre-stratified and damaged in advance. Under the action of mine pressure, the pressure fracture network develops three-dimensionally in space, constructing a more complex three-dimensional crack, further damaging the rock mass strength and integrity, making it difficult to form energy accumulation and stress concentration, reducing the dynamic load impact on the support-surrounding rock system, and the roof after strength damage is more likely to achieve post-support roof cutting under the action of the high roof cutting force of the ultra-high resistance support, thus further reducing the stress on the support-surrounding rock system in the stope. Space synergy means that the high-strength support of the stope support body is mainly reflected in timely supporting the surrounding rock mass after being cut and exposed by the shearer, preventing the further instability of the damaged near-field surrounding rock mass and maintaining the stability of the near-field surrounding rock mass. Regional fracturing is to transform the far-field roof, changing the stress environment and overlying rock structure above the roof under the action of fracturing, and relieving the force source causing the instability of the near-field support-surrounding rock system from a higher level.

[0129] The collaborative control method of the hard and thick roof in the coal mining face according to the embodiment of the present invention can collaboratively control the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support. Thus, through the strong support of the ultra-high resistance support of the target hydraulic support and the regional fracturing technology based on the process parameters of the area to be fractured underground, the collaborative control of the surrounding rock in the extra-thick coal seam mining face is carried out, effectively reducing the intensity of mine pressure manifestation in the working face and ensuring the mining safety of the coal mining face.

[0130] Based on the above description, the embodiment of the present invention gives an example of the collaborative control method of the hard and thick roof in the coal mining face.

[0131] Among them, in an embodiment of the present invention, taking a 10m ultra-large mining height working face of a certain coal mine as an example, the collaborative control method for the hard and thick roof of the above coal mining working face is described as follows:

[0132] S1. Determine whether the coal mining working face meets the collaborative control conditions.

[0133] S11. Use the leakage amount observation method to determine that the corresponding first height of the caving zone of the above ultra-large mining height working face is 41.7m, the caving ratio is 5.05, the corresponding second height of the fissure zone is 167m, and the fissure ratio is 22.56;

[0134] S12. Use the key stratum theory to judge the key stratum structure of the coal seam roof, and it is obtained that there are 3 strata within 80m above the coal seam. Among them, the key strata located (or partially located) within the caving zone are mainly 2 strata, which are siltstone with a thickness of 19.52m and medium-grained sandstone with a thickness of 18.8m from bottom to top in sequence. Based on this, it is determined that there are 2 hard and thick rock strata (or key strata) within the caving zone of the working face in this area;

[0135] S13. Determine the target working resistance of the hydraulic support corresponding to the second structure (the above cantilever beam and articulated rock beam structure) based on the second formula;

[0136] Among them, according to Figure 2 Analysis of the roof rock stratum structure, the immediate roof above the coal seam is 6.85m thick in total, consisting of interbeds of siltstone and fine-grained sandstone. Above it is 11.5m thick siltstone, which constitutes the lower sub-key stratum of the working face. The 18.8m thick medium-grained sandstone above is the follower stratum of the upper sub-key stratum. The area below this stratum is regarded as the caving zone range, with a total height of 30m. Among them, the immediate roof is relatively thin and it is difficult to fill the goaf. Based on this, the lower sub-key stratum cannot form a masonry beam structure, but exists in the form of a cantilever beam structure. The lower sub-key stratum is located within the caving zone of the working face, and the upper sub-key stratum periodically fractures to form an articulated rock beam structure. Thus, under this roof condition, the working face forms the structural characteristics of "cantilever beam + articulated rock beam".

[0137] And, according to the results of the physical and mechanical tests of the roof rock strata and coal, taking the unidirectional tensile strength of the medium-grained sandstone as 2.85MPa, the unidirectional tensile strength of the siltstone of the lower sub-key stratum as 3.0MPa, and the rock unit weight as 24kN / m3, substituting into formula (3) gives: the periodic fracture step distance L1 of the cantilever beam of the lower sub-key stratum = 20.4m, and the periodic fracture step distance L2 of the masonry beam of the upper sub-key stratum = 22.4m.

[0138] Furthermore, through the above steps, it is obtained that there are two hard and thick rock strata within the caving zone. It is necessary to substitute the numerical values of the above parameters into the formula of "cantilever beam + articulated rock beam" (the second formula above) to calculate the working resistance of the support, and the target working resistance is obtained as 50000 kN.

[0139] S14. Through the above steps, the target working resistance is obtained as 50000 kN. At present, the maximum working resistance of the ultra-large mining height hydraulic support is 29000 kN, which cannot meet the requirements of roof support. It is determined that the coal mining face meets the conditions of collaborative control. That is, it is necessary to weaken the hard and thick roof such as 11.5 m thick siltstone and 18.8 m thick medium-grained sandstone, improve the caving property of the roof, and reduce the lamination thickness and caving step distance.

[0140] S2. If the coal mining face meets the conditions of collaborative control, then determine the process parameters of the hard and thick roof corresponding to the area to be fractured.

[0141] Among them, according to the mechanical properties of the rock stratum to be fractured, determine the regional fracturing process parameters of the fracture pressure, hydraulic fracture propagation radius, borehole layout plan and segmented fracturing spacing corresponding to the area to be fractured of the hard and thick roof.

[0142] Specifically, according to the analysis of the hard and thick roof horizon, it is determined that the target rock stratum for regional fracturing is 11.5 m thick siltstone and 18.8 m thick medium-grained sandstone, and the fracturing horizons are 15 m and 35 m. According to the in-situ stress test of the coal mine and the test results of the roof rock mechanical parameters, the maximum horizontal principal stress of the sandstone roof of the 2-2 coal seam is distributed between 3.3 and 20.5 MPa, the average uniaxial compressive strength of the hard sandstone roof is about 50 MPa, and the maximum tensile strength value is 3.12 MPa. Based on this, it is calculated that the fracture pressure of the hard roof rock stratum is not less than 15 MPa, and the required pumping pressure to be satisfied is 15 - 32 MPa. Based on this, it is determined that the complete set of underground regional fracturing technical equipment needs to reach a single pump flow rate of 1.5 m 3 / min, the pump station pressure is 70 MPa, the measured fracture radius > 40 m, the borehole diameter is Φ120 mm, the maximum depth of the fracturing borehole is 800 m, the depth of the horizontal borehole is 400 - 650 m, the horizontal spacing of the boreholes is 80 m, and the backstepping segmented composite fracturing process is adopted.

[0143] S3. Determine the support parameters of the hydraulic support for the coal mining face, and determine the target hydraulic support based on the support parameters of the hydraulic support.

[0144] Among them, from the perspective of facilitating the control of the working face roof and coal wall spalling, select the type of hydraulic support, and determine the reasonable working resistance, support type and rib protection form of the hydraulic support.

[0145] Specifically, based on the target working resistance of the hydraulic support and considering a certain safety factor, the rated working resistance of the hydraulic support for the 10m ultra-large mining height working face is selected as 29000kN; the support type is a two-column shield hydraulic support, with a three-stage rib protection structure, and the total length of the rib protection is not less than 5.0m to facilitate automatic control and rib spalling management. Based on this, the hydraulic support model ZY29000 / 45 / 100D is selected according to the above parameters, with a rated working resistance of 29000kN, a support intensity of 1.88 - 1.95MPa, a total length of 5.5m for the three-stage rib protection plate, and a flexible protection wing is set on the rib protection plate between the supports to prevent the falling blocks from the coal wall from slipping out between the supports. The rated initial support force of the support is 37.5MPa, and it is equipped with a self-boosting system to ensure a high initial support force level.

[0146] S4. Based on the process parameters of the area to be fractured and the target hydraulic support, collaborative control is carried out on the hard and thick roof of the coal mining face.

[0147] Among them, during the above collaborative control process, during the coal face mining process, a mine pressure monitoring system is used to monitor the stress of the support in real time, and the matching degree between the support capacity and the mine pressure intensity of the working face is analyzed. Specifically, according to the actual measurement and statistics of the working resistance of the working face supports, after the fracturing in the implementation area, the end-of-cycle resistance of the supports is mainly distributed in the range of 20000 - 26000kN (accounting for 81.1%), (as Figure 8 shown), and the existing support working resistance meets the roof support requirements. In order to give full play to the support performance of the ultra-high resistance hydraulic support, the 10m ultra-large mining height working face improves the active support effect of the support and the system stiffness of the support - surrounding rock through high initial support force, and the average initial support force of the support reaches 34MPa (as Figure 9 shown).

[0148] In addition, a microseismic monitoring system is used to monitor and analyze the density of large-energy microseismic events and the stratigraphic changes of the working face roof, as Figure 10a and 10b shown. It is statistically shown that during the period from July 22 to August 15, 2024, a total of 337 roof breakage microseismic events occurred in the 122104 working face, with a total roof breakage energy of 1.8E+05J. Among them, there were 300 events with a power of 2, accounting for 89.02%, and the proportion of large-energy microseismic events with a power of more than 4 was less than 1%. The roof breakage strength was relatively weak. Among them, in the vertical distribution of microseismic events, the roof breakage energy in the 40 - 80m stratigraphic layer was 1.18E+05J, accounting for 67.27%. The height of the energy aggregation stratigraphic layer was 40 - 50m, indicating that after fracturing the hard and thick roof below 35m, the microseismic events in the lower stratigraphic layer of the roof were significantly reduced.

[0149] Further, a three-dimensional lidar method is used to observe the filling degree of the gob area behind the working face supports. The space behind the supports has been fully caved and solidified, the fragmentation degree of the directly roof broken blocks is small, and no obvious cavities are found. The maximum volume of the cavities is less than 2 m 3 .

[0150] Moreover, according to the above monitoring results, the corresponding evaluation result is normal. At this time, good results have been achieved in the collaborative control of the support unloading of the 10 m extra-large mining height working face, and no parameter adjustment is required.

[0151] Figure 11 It is a schematic structural diagram of the collaborative control device 1100 for the hard and thick roof of the coal mining working face in an embodiment of the present invention.

[0152] As Figure 11 shown, the device may include:

[0153] The first determination module 1101 is configured to determine whether the coal mining working face meets the collaborative control conditions;

[0154] The second determination module 1102 is configured to determine the process parameters of the area to be fractured corresponding to the hard and thick roof if the coal mining working face meets the collaborative control conditions;

[0155] The third determination module 1103 is configured to determine the support parameters of the hydraulic supports in the coal mining working face and determine the target hydraulic supports based on the support parameters of the hydraulic supports;

[0156] The collaborative control module 1104 is configured to perform collaborative control on the hard and thick roof of the coal mining working face based on the process parameters of the area to be fractured and the target hydraulic supports.

[0157] In an embodiment of the present disclosure, the above-mentioned first determination module 1101 is specifically configured to:

[0158] Based on the first height and the second height, determine whether there is a hard and thick rock stratum or a key stratum within the caving zone of the coal mining working face;

[0159] If there is no hard and thick rock stratum or key stratum within the caving zone of the coal mining working face, determine the target working resistance of the hydraulic supports corresponding to the first structure;

[0160] If there is a hard and thick rock stratum or key stratum within the caving zone of the coal mining working face, determine the target working resistance of the hydraulic supports corresponding to the second structure;

[0161] Based on the target working resistance, determine whether the coal mining working face meets the collaborative control conditions.

[0162] In an embodiment of the present disclosure, the above-mentioned first determination module 1101 is further configured to:

[0163] Determine the target working resistance of the hydraulic support corresponding to the first structure through the first formula, where the first formula is:

[0164]

[0165] where B is the center distance of the hydraulic support; l k is the roof control distance; Σh1 is the thickness of the immediate roof; γ z is the bulk density of the immediate roof; L is the periodic weighting interval of the main roof; is the friction angle between rock blocks; α is the fracture angle of rock blocks; h1 is the thickness of the main roof; S1 is the subsidence of the broken rock block of the main roof; Q is the total weight of the exposed rock blocks in the lower strata of the fissure zone above the working face roof.

[0166] In an embodiment of the present disclosure, the above-mentioned first determination module 1001 is further configured to:

[0167] Determine the target working resistance of the hydraulic support corresponding to the second structure through the second formula, where the second formula is:

[0168]

[0169] where h 垮 is the distance from the roof interface rock stratum of the caving zone to the coal seam; h2 is the thickness of the lower strata of the fissure zone; L1 is the cantilever length of the cantilever beam; L2 is the periodic caving interval of the hard rock stratum; S2 is the subsidence of the lower strata of the fissure zone.

[0170] In an embodiment of the present disclosure, the above-mentioned first determination module 1102 is specifically configured to:

[0171] Determine the fracture pressure of the hydraulically fractured rock stratum according to the in-situ stress field data and the rock tensile strength of the area to be fractured, so as to determine the target hydraulic fracturing pumping station;

[0172] Determine the hydraulic fracture propagation radius of the area to be fractured;

[0173] Determine the borehole layout plan according to the distribution parameters of the hard and thick roof;

[0174] Determine the staged fracturing spacing according to the hydraulic fracture propagation radius.

[0175] In an embodiment of the present disclosure, the above-mentioned collaborative control module 1104 is specifically configured to:

[0176] Actively support the near-field roof of the extraction space of the coal mining face through the target hydraulic support;

[0177] According to the borehole layout plan, fracture pressure, and staged fracturing spacing, a staged retreating fracturing is carried out in the borehole using a packer to perform staged fracturing on the boreholes in the area to be fractured until the conditions for ending fracturing are met, and then the pump is stopped to end the fracturing.

[0178] In an embodiment of the present disclosure, the above device is further configured to:

[0179] Obtain the monitoring and analysis results during the collaborative control process;

[0180] Evaluate the collaborative control based on the monitoring and analysis results to obtain an evaluation result;

[0181] Based on the evaluation result, dynamically adjust the process parameters of the fracturing area.

[0182] The collaborative control device for the hard and thick roof of the coal mining face in the embodiment of the present invention can perform collaborative control on the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support. Thus, through the strong support of the ultra-high resistance support of the target hydraulic support and the area fracturing technology based on the process parameters of the area to be fractured underground, the collaborative control of the surrounding rock of the extra-thick coal seam mining face is carried out, effectively reducing the intensity of the mine pressure manifestation on the working face and ensuring the mining safety of the coal mining face.

[0183] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0184] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

Claims

1. A method for collaborative control of hard and thick roof of a coal mining face, characterized in that: The method comprises: Determining whether the coal mining working face meets the coordinated control conditions; If the coal mining working face meets the coordinated control conditions, then determining the process parameters of the hard and thick roof corresponding to the area to be fracturing; Determining hydraulic support support parameters of the coal mining face, and determining a target hydraulic support based on the hydraulic support support parameters; Based on the process parameters of the area to be fracturing and the target hydraulic support, the hard and thick roof of the coal mining working face is coordinated and controlled.

2. The method according to claim 1, characterized in that The determining whether the coal mining working face meets the coordinated control conditions includes: Determine a first height of the collapse zone and a second height of the fracture zone corresponding to the coal mining working surface; Based on the first height and the second height, determining whether there is a hard and thick rock layer or a key layer within the collapse zone of the coal mining working face; If there is no hard and thick rock layer or key layer within the collapse zone of the coal mining working face, determining the target working resistance of the hydraulic support corresponding to the first structure; If there is a hard and thick rock layer or a key layer within the collapse zone of the coal mining working face, determine the target working resistance of the hydraulic support corresponding to the second structure; Based on the target working resistance, determine whether the coal mining working face meets the coordinated control conditions.

3. The method according to claim 2, characterized in that The determining the target working resistance of the hydraulic support corresponding to the first structure includes: determining the target working resistance of the hydraulic support corresponding to the first structure by using a first formula, wherein the first formula is: Wherein, B is the center distance of the hydraulic support; l k is the distance between the top and the control top; Σh1 is the thickness of the direct top; γ z is the direct top bulk density; L is the old top cycle pressure step; is the friction angle between rock blocks; α is the rock breaking angle; h1 is the thickness of the old roof; S1 is the sinking amount of the broken rock blocks of the old roof; Q is the total weight of the exposed rock blocks in the lower rock layer of the fracture zone above the top plate of the working face.

4. The method according to claim 2, characterized in that: The determining the target working resistance of the hydraulic support corresponding to the second structure includes: determining the target working resistance of the hydraulic support corresponding to the second structure by using a second formula, wherein the second formula is: Among them, the h 垮 is the distance between the top interface rock layer of the collapse zone and the coal seam; h2 is the thickness of the underlying rock layer in the fracture zone; L1 is the cantilever length of the cantilever beam; L2 is the periodic collapse step of the hard rock layer; S2 is the subsidence of the underlying rock layer in the fracture zone.

5. The method according to claim 1, characterized in that The process parameters for determining the hard and thick roof corresponding to the area to be fracturing include: Determine the fracture pressure of the hydraulically fractured rock formation based on the geostress field data and rock tensile strength of the area to be fractured, so as to determine the target hydraulic fracturing pump station; Determining the hydraulic fracture extension radius of the area to be fractured; Determining a drilling arrangement plan according to the distribution parameters of the hard and thick roof; The segmented fracturing spacing is determined according to the hydraulic fracture expansion radius.

6. The method according to claim 3, characterized in that The coordinated control of the hard and thick roof of the coal mining face based on the process parameters of the area to be fractured and the target hydraulic support includes: Actively supporting the near-field roof of the mining space of the coal mining face by means of a target hydraulic support; According to the drilling arrangement, the bursting pressure and the staged fracturing spacing, staged retreat fracturing is performed in the borehole using a straddle packer to fracture the boreholes in the area to be fractured stage by stage until the fracturing termination conditions are met, then the pump is stopped to terminate the fracturing.

7. The method according to claim 1, characterized in that The method further comprises: Obtain monitoring and analysis results during collaborative control; Evaluate the collaborative control according to the monitoring and analysis results to obtain an evaluation result; Based on the evaluation results, the process parameters of the fracturing area are dynamically adjusted.

8. A coordinated control device for hard and thick roof of coal mining working face, characterized in that: The device comprises: A first determination module is used to determine whether the coal mining working face meets the collaborative control conditions; The second determination module is used to determine the process parameters of the hard and thick roof corresponding to the area to be fracturing if the coal mining working face meets the coordinated control conditions; A third determination module is used to determine the hydraulic support support parameters of the coal mining working face, and determine the target hydraulic support based on the hydraulic support support parameters; A collaborative control module is used to collaboratively control the hard and thick roof of the coal mining face based on the process parameters of the area to be fracturing and the target hydraulic support.

9. A computer storage medium, wherein: The computer storage medium stores computer executable instructions; after the computer executable instructions are executed by the processor, any method described in claims 1-7 can be implemented.

10. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

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